This invention relates to amplifiers and more particularly to a microwave power amplifier.
In the past 6-18 GHz medium power amplifiers have been fabricated as hybrid type circuits. That is, the circuit elements such as, for example, the transistors, capacitors, and resistors have been discrete devices mounted on insulating substrates or metal carriers and interconnected with bonded wire leads.
The disadvantages of the prior art hybrid power amplifiers are cost and producibility. Highly skilled operators are required to assemble the hybrid amplifiers, and the manufacturing tolerances achievable with manual asembly methods result in significant performance variations between amplifiers. This necessitates that each circuit be tuned by a skilled test technician to meet the performance specifications.
The labor invested in each circuit results in an expensive product which cannot be produced in high volume quantities.
Accordingly, it is an object of this invention to provide a microwave power amplifier which is low in cost, easy to fabricate using mass production techniques and highly reliable.
Another object of the invention is to provide a substantially symmetrical circuit that can be easily used in a balanced amplifier configuration, allowing the option of applying bias supply voltages from either side of the chip.
Still another object of the invention is to provide a monolithic medium power amplifier, fabricated on a GaAs substrate.